Enzymes are proteins which catalyze chemical reactions. In enzymatic reactions, the molecules upon which an enzyme acts are called substrates, and the enzyme converts them into different molecules called the products. Enzymes are usually very specific as to which reactions they catalyze and the substrates that are involved in these reactions.
The internal dynamics of enzymes is connected to their mechanism of catalysis. Internal dynamics are the movement of parts of the enzyme's structure, such as individual amino acid residues, a group of amino acids, or even an entire protein domain. These movements occur at various time-scales ranging from femtoseconds to seconds. Networks of protein residues throughout an enzyme's structure can contribute to catalysis through dynamic motions.
Protein motions are vital to many enzymes, but whether small and fast vibrations, or larger and slower conformational movements are more important depends on the type of reaction involved. Complementary shape, charge and hydrophilic/hydrophobic characteristics of enzymes and substrates are responsible for this specificity. Enzymes can also show impressive levels of stereospecificity, regioselectivity and chemoselectivity. The tight control of enzyme activity is essential for homeostasis, any malfunction (mutation, overproduction, underproduction or deletion) of a single critical enzyme can lead to disease. The importance of enzymes is shown by the fact that a lethal illness can be caused by the malfunction of just one type of enzyme out of the thousands of types present in the organism.
Several clinical conditions, such as unstable plaque, metastasis, tissue regeneration, etc. are related to enzymatic disorders.
Most biological matter is diamagnetic in nature having negative magnetic susceptibility. For the purposes of the present invention, magnetic particle are defined as any non diamagnetic composition of particles, crystals, molecules or ions. These particles attached to a protein will produce a magnetic signature different from that of the protein itself. Such magnetic signature is a function of the size and shape of the particles. Magnetization of a given material is defined as its average magnetic moment per unit volume and is determined by their internal structure and composition. Some magnetic particles of interest are the paramagnetic, superparamagnetic and ferromagnetic particles which are commonly utilized as contrast agents as single particles, microencapsulated in matrices or attached to other molecules. These magnetic agents are designed to maintain their magnetic properties constant over measurements and produce imaging effects according to their concentration and distribution at different body compartments and tissues.
There thus remains an unmet need to develop diagnostic methods for diagnosing or detecting diseases which are related to enzymatic disorders and further to develop methodologies for monitoring the progression of these diseases in mammalian subjects.